Multi-die packaging with chiplets is crucial for high-performance data centers and aerospace and defense solutions, demanding advanced packaging technologies. The UCIe Consortium's 2.0 specification promises significant bandwidth, density, and power efficiency advancements. Modern chiplet designs feature hundreds of single-ended signals operating at 16 Gb/s, with 32 Gb/s on the horizon. Accurate modeling of these dense interconnects is critical for reliable package substrate design. This presentation demonstrates a workflow for analyzing and mitigating crosstalk in a 16 Gb/s UCIe die-to-die interface that employ a single macro to represent the interface and analyze crosstalk effects from multiple single-ended nets within the same macro. By identifying the worst-case aggressor, we strategically incorporate additional return vias to enhance signal integrity and improve eye diagram quality. This workflow provides a robust approach for the sign-off of advanced package designs for demanding chiplet applications.